Update master vs develop branch

[abcummins]

Hello, I'm new to this project and am interested in contributing to it if the project is still being maintained. @AndreiShilov, I saw you were the last one to have any activity on the project.
As stated in the title I would like to consolidate and/or better explain in the contributing guidelines what is going on between the master and develop branch, they seem to have different features and haven't been merged in a while.